just started the 2391

[i=p/u]

this thread will go on for quite a while (14 WEEKS), to exams... ive nearly read gn3 for the first time and there is a few things i dont fully understand but im sure i will for when the time comes from help from you guys/dudes/punks who know just a little to much.

 

[ANDY FIRST]

No power given for that motor m8!?!...

 

[efcsnakes]

phase rotation instruments, 1)audio phase rotation instrument 2) visual phase rotation instrument...

you are looking into the questions to much... there just looking for simple answers...

as for the motor circuit it's classed as power so your allowed 5% max drop... so L x Ib x (mV/a/m)/1000 =VD...
then VD/source Voltage x 100 = Volt drop % you must have been given the information to work this out...

 

[i=p/u]

i believe they looking simple awnsers... ive been readding that exam sucess and tells you how to swnser the questions.. which makes sense... i didnt do the exam in a time limit just give myself the awnsers and i would of got most of them right.. good book tells you areas to cover and stuff.

intersting that markie sparkie says about the new amendment... i thought we would of went by te red book cause we booked on course before cut off date , but they extended it..

as for the volt drop question above i would of got that.

when do you have to add in conductor operating temp as factor in relation to vd.?

 

[efcsnakes]

don't complicate the answer. they won't ask in the 2391 exam about correction factors on volt drop.. that's more for design and verification course....

 

[i=p/u]

addicted

 

[MarkieSparkie]

phase rotation instruments, 1)audio phase rotation instrument 2) visual phase rotation instrument...

Hi i=p/u, Ensure you don't use the terms "phase rotation test or tester" C&G are hot on this, PHASE SEQUENCE TEST or TESTER are the approved terms. Also approved testers are the rotating disc type and indicator lamp type (See 612.12 and GN3 2.7.17).

 

[efcsnakes]

Hi i=p/u, Ensure you don't use the terms "phase rotation test or tester" C&G are hot on this, PHASE SEQUENCE TEST or TESTER are the approved terms. Also approved testers are the rotating disc type and indicator lamp type (See 612.12 and GN3 2.7.17).

Phase rotation instrument is the correct term as per GN3 section 4.8, if you have a look at the following. In the first paragraph on the last couple of lines it states that the phase rotation instrument can be "Mechanical, visual and/or audible". phase sequence is the type of test not the measuring device.

 

[GLENNSPARK]

if and when you get your hands on past papers n stuff what will become apparant early on is how the same kind of questions are asked.....just in different ways.....variations on a theme here...but it does throw a lot of people.....a typical scenario will have sensitive equipment and variable resistors (dimmers)....so you know that someware along the line their going to ask you about dead testing (R1 R2...and IR).....this is a common one on this course.......

 

[Richard Burns]

Phase rotation instrument is the correct term as per GN3 section 4.8, if you have a look at the following. In the first paragraph on the last couple of lines it states that the phase rotation instrument can be "Mechanical, visual and/or audible". phase sequence is the type of test not the measuring device.

The Chief examiners report states that the instrument names accepted are those listed in chapter 4 of GN3 and therefore would be a phase rotation instrument.
However they are inconsistent in their descriptions in the reports; and in GN3, where it uses the term "phase sequence indicator" and states at various times you are checking the phase sequence and at other times the phase rotation. All very helpful.
It is the same with IR where they state use an insulation resistance tester, but the instrument in chapter 4 is an insulation resistance ohmmeter!

Because GN3 states two main type available as rotating disc type and indicator lamp type, this would be a better description than mechanical or audible.

 

[efcsnakes]

so the answer for the question in the 2391 would be "audible or visual phase rotation instrument", I know there are different and inconsistant descriptions but as you point out it is very clear what is acceptable in the chief examiners report. Those listed in chapter 4 of GN3

 

[i=p/u]

its a 2391 night

 

[i=p/u]

anyone know where i can find the labelled diagram of earthing , cpcs , bonding conductors that was in the red bs 7671. its obv not in green bs 7671

 

[i=p/u]

what about this one..an example of a C3 observation is earth leakage circuit breaker installed at origin of tt installation???? why is this as there is 1000s out there

 

[i=p/u]

i

anyone know where i can find the labelled diagram of earthing , cpcs , bonding conductors that was in the red bs 7671. its obv not in green bs 7671

do know

 

[Silly Sausage]

I=P/U

Just out of interest, are you a lover of Single Malt Irish Whiskeys, per chance?
(on a regular basis) :wink_smile::wink_smile: